N-Acetyl-Cysteine (NAC) Helps Alleviate COPD (chronic obstructive pulmonary disease)

The amino acid N-Acetyl-Cysteine (NAC) is an antioxidant, and is also the precursor to the body’s most powerful endogenous antioxidant—glutathione. Glutathione is considered the “master antioxidant” because unlike all the other antioxidants it doesn’t need any other antioxidants to help it do its job.

NAC was first developed as a dietary supplement to help break up mucus in the lungs in conditions such as bronchitis. But current studies are showing that it is an effective tool for slowing down the progression of, and easing the symptoms of COPD—chronic obstructive pulmonary disease.

Oxidative stress has been implicated in the both the cause and the progression of COPD. Free radicals from inhaled cigarette smoke, environmental pollutants and those formed in the body as a result of inflammation can damage and burden the lungs. In the case of COPD, structural changes take place in the lung tissues and airway walls, resulting in irreversible damage.

Long-time tobacco smokers have the highest risk of developing COPD. Once you get the diagnosis of COPD it’s pretty much assumed that your lung function will steadily decline overtime. Although air pollution and smoking aggravate COPD, the disease isn’t limited to people who smoke or who are exposed to environmental toxins. Eventually, the damaged airways of COPD patients may become colonized with dangerous bacteria, leading to chronic infection and even more inflammation. It then turns into a vicious cycle. Inflammation leads to infection, which leads to more inflammation, which leads to a decrease in lung function, and so forth.

The good news is there is significant experimental and clinical data showing that NAC has a strong antioxidative effect on COPD.1

A German randomized pilot study of adults with acute chronic bronchitis showed that 600 mg of NAC taken twice a day led to a near doubling of the rate of bacterial eradication compared with standard therapy. At the same time, NAC helped reduce other symptoms and improve quality of life. NAC also helped patients with moderate-to-severe COPD improve their physical performance on lung function tests, especially after exercise.2

A recent study done in Israel assessed the lung function of 24 COPD patients who took either 600 mg of NAC or placebo twice daily for six weeks. At the end of six weeks, the patients switched what they were taking, so that everyone ended up taking NAC by the end of the study.

The researchers measured various indicators of lung function during rest and after exercise at the beginning and end of the study. They found that when the patients took NAC they experienced improved lung function, and the amount of air they were able to inhale and exhale. Their exercise endurance also improved.

The researchers attributed the overall improvement in lung function to a reduction in “air trapping”—or a better exchange of air in alveoli, the parts of the lung where inhaled and exhaled air are transferred.3

Besides alleviating symptoms of COPD, NAC has been shown to:

  • raise antioxidant levels
  • support memory and brain function
  • improve immune function
  • have anti-aging properties
  • help support eye function

NAC can reduce frequency and severity of flu-like symptoms in the elderly and high-risk individuals

An Italian study evaluated the effect of 600 mg of NAC versus placebo twice daily for six months on 262 men and women. The participants were from 20 different health centers. They were older than 65 years of age, and had non-respiratory chronic degenerative diseases. Each of the subjects was given a diary and asked to keep track of symptoms such as fever, muscular weakness, loss of appetite, headache, aches and pains, nasal discharge, sore throat and cough. Researchers defined influenza-like episodes as when two or more of the symptoms occurred at the same time.

According to the researchers, the overall frequency of patients suffering from influenza-like episodes was significantly lower in those who received NAC, in comparison to those who received the placebo. Of the patients with laboratory-confirmed flu, only 2% of the NAC group developed symptoms, compared with 79% of the placebo group.

Of the flu-like cases among people taking NAC, 72% were mild, 26% were moderate, and % were severe. In the placebo group, 48% of the infections were mild, 47 percent were moderate, and 6% were severe. Also, the length of time that patients with the flu spent in bed was much shorter in those who took NAC. Nine of the 10 subjects who had the flu and were not bedridden received NAC.4

This study is especially encouraging news for the elderly, since flu vaccinations have been proven ineffective.*5

What is COPD?

COPD, or chronic obstructive pulmonary disease, is a progressive disease that makes it hard to breathe. COPD is a major cause of disability, and it’s the fourth leading cause of death in the United States. More than 12 million people are currently diagnosed with COPD. An additional 12 million likely have the disease and don’t even know it.

COPD develops slowly. Symptoms often worsen over time and can limit your ability to do routine activities. Severe COPD may prevent you from doing even basic activities like walking, cooking or taking care of yourself.

COPD can cause coughing that produces large amounts of mucus, wheezing, shortness of breath and chest tightness.

Most of the time, COPD is diagnosed in middle-aged or older people. The disease isn’t passed from person to person—you can’t catch it from someone else.6

Although there is no medical cure for COPD yet, it appears that NAC can help some individuals feel better, stay more active and slow the progress of the disease.

* Vaccine effectiveness was estimated to be 5% for the 2004-05 season, 11% for 2005-06 and 37% for 2006-07. The percentage of viruses matching the vaccine was 5% for 2004-05, 5% from 2005-06 and 91% from 2006-07. Conclusion: Vaccine effectiveness varies and is highest when the shot matches most closely to circulating viruses.


  1. Dekhuijzen PN, van Beurden WJ. The role for N-acetylcysteine in the management of COPD. Int J Chron Obstruct Pulmon Dis. 2006;1(2):99-106.
  2. Reichenberger F, Tamm M. N-acetylcystein in the therapy of chronic bronchitis. Pneumologie. 2002 Dec;56(12):793-7.
  3. Stav D, Raz M. Effect of N-acetylcysteine on air trapping in COPD: a randomized placebo-controlled study. Chest. 2009 Aug;136(2):381-6. Epub 2009 May 15.
  4. De Flora S, Grassi C, Carati L, “Attenuation of influenza-like symptomology and improvement of cell-mediated immunity with long-term N-acetylcysteine treatment,” European Respiratory Journal, 1997;10:1535-1541.
  5. Belongia EA, Kieke, BA, Donahue, JG, et. al. “Effectiveness of Inactivated Influenza Vaccines Varied Substantially with Antigenic Match from the 2004-2005 Season to the 2006-2007 Season,” abstract, Journal of Infectious Diseases, Jan. 15.
  6. National Health, Lung and Blood Institute, National Institutes of Health.